This is a picture of the battery case and charging electronics after I unsoldered the original li-ion cells.
Here I have two Li-Ion cells ready to solder together into a parallel pack. The technique that I found to work best was to insert a coil of small electronic solder between the tab and the bottom of the next battery, making sure that the solder never overlapped, so that their was always only one thickness of solder thick at any particular place. Then, I'd hold down the end of the tab with a screwdriver (to make sure it didn't bounce back up while the solder was still hot) and heat the tab with heavy downward pressure from a heavy duity (stained glass) soldering iron for a few seconds. I'd press down until the solder visiblely melted (usually accompanied by a puff of resin smoke) and the tab settled down. Then I'd remove the iron while keeping pressure with the screwdriver.
Important safety note: At the factory, tabs are welded to li-ion cells very quickly. Li-Ion cells will catch fire explosively if they are overheated. It is very important that you do not leave a soldering iron on the cells long enough to raise their internal temperatures to dangerous levels. Heat the tab, melt the solder, and then remove the iron.
You will note that I used one set of tabs to attach the two cells, and the other set of tabs was positioned 90 degrees off axis, to be used to connect to other packs of cells. Note that I'd use tape to hold the cells closely together while soldering them, but would remove the tape later to make them fit into the battery holder.
Here is my first pack, soldered to the charging electronics. Note that I have temporarily covered the exposed positive ends of these cells with clear plastic tape. This tape insulation is very important! It keeps this pack of cells from accidentally shorting through the pack of cells that I will add next. The process involves laying the cells on top of each other while soldering, and it is very dangerous to short out li-ion cells. (All of the charging electronics and fuses in the battery are designed just to keep that from happening.) Note that other things on your workbench can short out li-ion cells. For example, a coil of solder conducts electricity very well, at least until it melts. So do screwdrivers and pliers, and they are less likely to melt. Li-Ion cells are usually stored and shipped 40% full to prolong their life, and the ones I had certainly did spark a few times. A small spark here or there won't hurt anything, but if you short a cell for longer than a moment, it will begin to overheat and you could get into a runaway situation where it eventually catches fire explosively. Don't do that!
Once I've safely insulated the ends of these cells, I add the 2nd pack and solder them together.
After the tabs are soldered together, you can unfold the 2nd pack and lay it down flat.
When soldering existing metal tabs from the charging electronics to the cells, I found it best to coat the tabs with solder first, and then attach them to the cells. Below you can see a pre-existing tab that I pre-soldered before attempting to attach it to the back of the cells.
Note that the first and second pack have a good space between them (by design) in the battery holder, which leaves plenty of room for the solder tabs to be folded between the two packs of cells. However, the second and third packs must be mounted much closer together. Because I did not have a custom manufactured set of solder tabs, I found it easier to just butt the batteries up against each other and join the solder tabs above the cells.
Now, I have all three packs connected in serial, and to the charging electronics. All that remains is to find some very sticky double-sided tape to affix everything to the interior of the battery case. I suggest you use carpet-tape (designed for tacking down carpet), which appears to be about as strong as the original tape I removed from the case when disassembling it.
Once the tape is in place, all that remains is to snap the two halves of the battery case together, being careful to get all of the tabs in the right slots. Everything snaps together with a satisfying "clicking" noise, and the battery is as good as new. If you do not remove the manufacturers sticker (as I did) and are careful to use a plastic tool and not leave scrape marks when prying the battery apart (as, once again, I did) the battery will look practically like new.
But how does our existing charging charging circuitry deal with the brand new li-ion cells?
Related posts:
99 comments ↓
HOW TO – Refilling laptop batteries…
Jay writes – Here’s a step by step tutorial on how to “refill” laptop batteries by replacing the Li-Ion cells. By purchasing higher capacity cells than your laptop uses normally, you can super-charge your battery life! Jay’s Technical Talk……
Jay, thanks so much for the Info! I had never even thought of that!
I bought an old panasonic toughbook for my daughter from ebay, and of course, the battery was dead. cost of a replacment on ebay: about a hundred bucks. a quick google search for the cells found them at about 3.50 each. total cost for 9 cells plus shipping:$45.26
you just saved me at least 50 bucks!
Thanks again! -
Great stuff!
Thanks for mentioning explosive batteries. They really stink too.
Its pretty easy to injure the batteries even if you dont explode them with the soldering iron. (= less capacity)
DIY: Refill Your Own Laptop Batteries…
Everyone knows that after a substantial amount of use, laptop batteries are destined for failure, but hold your horses before clicking the “Buy” link on a new $100-plus laptop battery. Jay picked up some OEM lithium-ion batteries and decided to……
Warning, from the voice of experience: in addition to taking care to not overheat cells while soldering, also take care to not physically damage or deform the cells such as dent, ding or put undue pressure on them when re-assembling. Any physical damage can lead to an internal short and if the battery has sufficient charge, it will overheat and leak, smoke and/or explode, in that sequence.
BEWARE !!! , not all notebook battery can be refill like this way , some new smart notebook battery got a flash chip inside , when u took off the battery the chip is automatic erase , so you never can recharge your battery , even you change the new cell inside, u only can refill some old nb battery like 5 or 6 year old notebook !
How to know if flash chip is present on battery?
BTW Very nice howto
Plesae could someone tell me where I can purchase these batteries from!?!? The ones that go inside the battery pack.
I bought the batteries (li-ion cells) from http://www.batteryspace.com (it’s listed on the first page of the post.) Others sell them too, if you do a search for “18650 li-ion” on froogle.com plenty of dealers come up.
ラップトップの電池をDIYで交換する方法…
ラップトップのバッテリーって遅かれ早かれ寿命がくるものです。 新品は100……
I got IBM R32 LAPTOP please advise how to open the battery pack and replace with an OEM cells..? Do you have some pics
Much appreciated. Best regards
The R batteries should be very similar to the X batteries. I used a Cell Phone opening tool (Green plastic pry bar) to gradually crack open the battery at the seam and “un-snap” each of the clip in snaps that hold the two halfs together.
I followed your lead and rebuilt my A20m’s battery pack (original IBM # 02K6618). I bought my cells from batteryspace and got the 2600 mAh cells. Worked great! Now, about resetting that flash chip…my pack has an AS358D flash chip. I’ve spent a lot of time looking on the web for info on reflashing the chip, and have only found one thing: “Smart Battery Workshop,” a program that claims it can read and reflash the chip. Problem: another company bought the program’s creators, and now only rebuilds batteries for you. The program was apparently well copy-protected and I can’t find a hacked copy. If anyone can find a way to reset the flash chip, we’ll all be good-to-go.
For those of you not as technicly inclined as most on this forum, and who consider refilling your batteries as a cheaper means of getting your old laptop back in order, this comment is for you. Beware refill services like Batteryrefill.com or the like who promise a “quick turnaround.” If you are the type who needs your laptop for flexibility and needs it often, you are better off buying a new battery rather than wait the 2+ months some of these services take to work on your batter.
Thanks for the great tutorial!
Would you have any advice on how to pry the battery case apart?
Lutz:
I used some plastic tools made for prying cell phones apart. It takes a bit of technique to do it without damaging the plastic. I basically get one of the two tools in place, and then slide it along while using the other tool to keep pressure on the crack.
I used one very much like the following: http://www.apscell.com/prytoolb.html
Jay
I replaced the 6 Li-ion cells in the pack for my IBM T40. I get great prices and service from allbattery.com. I guess I need to reflash the chip in the pack. The batteries measure 3.6 volts, but they won’t charge in the laptop. It sees the battery pack and says it’s 1% charged, but won’t charge.
[...] http://www.summet.com/blog/2007/02/17/laptop-battery-refill/3/ [...]
I thought doing this stuff to my X21 battery. The only problem is: I can’t even start because I’m unable to OPEN the battery case. It’s a tight seal. Did you find this in the X31 battery too?
Eddy:
Yes, the two halves are sealed together very well. I used some plastic “cell phone opening” tools to gradually pry the sides apart, working the crack along as I went.
Jay
>I have a curiosity question
> which I wonder if you have ever considered or heard of
> elsewhere: Substituting lower cost NiMH cells for the Li-
> Ion cells.
While NiMH cells can be used in a battery, you should NEVER replace LiIon cells with NiMH cells. The reason for this is that the charging electronics in the battery are designed for LiIon cells, which are able to receive a much faster charge than the NiMH cells. If you tried to charge NiMH cells with a LiIon charging circuit, they would likely burst, burn, or even explode! Now, if you were able to find a battery pack that was similar to your notebooks (perhaps for an earlier model notebook in the same series that used NiMH batteries, you could replace the (LiIon) charging circuit with the NiMH charging circuit, and then you could use NiNM batteries.
Hi Jay,
which OS and/or which tool do you use to check the capacity?
Greetings from Munich/Germany
Chris
I’m using Linux (with acpi enabled) to get the detailed battery information.
cat /proc/acpi/battery/BAT0/info
Jay
>Hi Jay,
>which OS and/or which tool do you use >to check the capacity?
I found a way to reset the full-charge capacity for Power Manager on WinXP. Follow instructions given by Jay, but perform a “battery gauge reset” between your full discharge/charge cycles.
An additional tip for this to work well is to fully discharge with all timers off, and then fully charge with the thinkpad switched off.
The results are:
- 1st reset: 8.76 to 12.73Wh
- 2nd reset: 12.73 to 13.33Wh (didn’t do something right????)
- 3rd reset: 13.33 to 18.62Wh
- 4th reset: 18.62 to 27.45Wh
- 5th reset: 27.45 to 37.23Wh
- 6th reset: 37.23 to 45.72Wh
- 7th reset: 45.72 to 52.99Wh??
Now my R51e runs for almost 4.5hrs before reaching 1% on “max battery life” settings! (I replaced the cells with 2600mAh!)
Can we do this with lithium polymer?
Robert:
Lithium Polymer cells are basically LiIon cells that are more flexible, so should work just fine for this type of application.
Jay, or anyone, do you know if there is a flash chip set in my Toshiba Satellite M45 S3553? thanks
Also tips for opening up the battery pack would be nice, thanks
hello! and do I can use the NiMH cells and just recharge it in outside recharger not in notebook?
QAD417: I do NOT recommend using NiMH batteries to replace Li-Ion cells. If you did, you could not use the built in laptop Li-Ion charging circuit. You would instead need to use a NiMH charger (either outside the notebook as you suggested, or somehow built into the battery pack). [Of course, if the original battery pack used NiMH cells, you could replace them with NiMH cells.]
My battery at the moment has 4 3.7v (totaling 14.8) cells in series. There is space for 8 cells (there is a large capacity model that uses the same battery case). Could I create 4 banks (in series) of 2 cells (in parallel), still giving 14.8v but doubling the capacity. Will the charging circuit be able to cope? Will the battery me more likely to overheat (I guess the current drawn from each cell will be less so it will be cooler)?
Nathan:
Technically, every cell should be controlled independently. (That is why your existing charging circuit should have a wire that goes to the connections between each cell to the next, so that it can control the charging current to each cell independently.)
However, as long as you stick with a matched set of cells, I expect that you should be 100% safe if you “doubled up” each cell (in parallel). To the charging circuit, it would look like each of it’s individual cells just got more capacity. You are also correct that the power draw from each cell would be halved so the temperature should be cooler. (I expect that your battery would also take twice as long to charge.)
You are indeed lucky to have a battery with extra empty space in it, what model/brand is your laptop?
Jay
Thanks for the quick reply? Now the battery is apart I can see there is only one wire to each pair of cells (actually to the connecter between the two). The laptop is an IPC Multimedia Desknote E (though I have seen it alternatively branded). The battery is an EM-G320L1 (I think made by Elitegroup Computing Systems).
How do you open the plastic case of the Compaq Presario R3000 laptop battery, a 14.8V 6600mAH?
Do I have to cut it open?
Are there any higher capacity cells?
Thanks
I did a restore of my X31 battery and have soldered everything up correctly (looking at your pictures and ones I took before removing old cells) and the battery wont charge.
Watching the temps under linux show they stay normal but the charge/discharge rate doesn’t change. I left it hooked up for 20 minutes and nothing changes…should I just leave it longer?
Adam: It took me about 5-8 charge/discharge cycles to get my new battery charged all the way up (or at least, reporting that it was charged all the way up.)
It could be that the firmware/chip in your original battery does not allow the cells to be “replaced”, but my suggestion is that you run your laptop all the way down every night (and then charge it all the way back up) for a week and see if anything improves.
Jay
Nathan, how did you open the EM-G320L1? There aren’t any screws and I don’t want to tear up the case by prying indiscriminately.
I just opened up my laptop Battery (for Averatec 2300). The computer wont turn on with the battery. I left it plugged to the ac adapter for at least 4 hours, still the battery charge is at 0%.
With the battery case opened up, I can see each battery is at 3.8V, totaling around 11.5V. I even measured voltage at the connector :11.5V. The cells are still good! I guess it’s the flash chip. What can I do?
Hi Jay,
My battery for my Sony Vaio is not charging anymore; so I decided to buy a new battery. The prices of the battery in Japan however is about $250.00, so I stated thinking about repairing the battery. Your explanation was clear and very helpful. Thanks very much. I am going to try and replace the cells. Wish me luck.
Thanks
Regards
Dev
Jay, I just replace 6 batteries in a Toshiba battery pack (quite a task when you have low quality soldering tools).
So far it is charging and has the power to boot up the laptop. Problem is… it is DRAINING LIKE CRAZY! I got 6x 2200mAH batteries and I believe the old ones were 1800ish maybe.
I’m about to do a 2nd full charge and see how it goes. Is this normal for the first few recharge cycles?
Quick update:
Still draining battery for the 1st time but at 6% it doesn’t seem to down anymore.
Duc Tien,
If by “Draining like crazy” you mean that after the first charge the battery level indicator goes down rapidly (during the first discharge), then yes, this matches what happened to me.
The best I can come up with is that the charge control circuit thinks that it is still using your old cells, so when it sees a lot of current leaving the cells it figures that they are rapidly getting close to their “zero” point, and makes the percentage of battery left indicator drop appropriately.
In my experience, my laptop would continue to run for quite a while after the battery indicator reached the zero percent mark. (as in, 20-60 minutes!).
After several (5-6) full charge/discharge cycles, the charging circuitry eventually learns that the new calls were “better” than the old cells. (In my case, the battery capacity “increased” by about 10% each charge/discharge cycle.)
Jay
[...] refilled the Li-ion cells in my laptop battery about 18 months ago.The battery has worked as expected since then. The only "special" [...]
Hi, I repair a 336962 battery for HP. I changed all the cells, but when i put the battery on my laptop, the battery appears with a red X. What can I do?
Thans,
César
César,
It is possible that your HP battery control chip does not allow cell replacement. Alternatively, the red X may go away after several charge/discharge cycles (if the battery is working correctly despite the red X).
Jay
Hello,
I am interested in running a radio transmitter from a laptop battery (Model#BATCL50L) then recharging using the laptop. I am not able to find the battery’s output connection.
Is their an internal disconnect that is used when the battery is unplugged?
Thank you
Martin Lee
+1 408 898 4095
Hi I have a DEll laptop. The batery keeps charge only 30 min. I bought the laptop about 1 year ago. Is it possiblefor me to repaire it?
thans
mohsen,
I don’t know if the Dell batteries firmware allow the cells to be replaced or not. You will have to ask somebody who has done it for a DELL battery. (Or just try it yourself.)
Jay
Hello Jay, thanks a lot 4 your valuable info. I wanna ask something:
1. How to determine whether the cell is death or still alive? Can I test it individually (in pair maybe)?
2. Is it OK to mix the new cell with the old one? (in case not all cells are die)
3. How to determine the problem is the cells or the charging circuitry?
Thank you Jay, maybe a bit too much questions eh? I’m sorry for that. Would you please send me a copy of your answer to my e-mail? I’m not always connected.
Erdwi,
> 1. How to determine whether the cell is death or still alive? Can I test it individually (in pair maybe)?
You would have to test them individually. Charge the cell, and then discharge them through a load (motor? Lightbulb?) and watch how long it takes to drop X amount of voltage to estimate it’s current storage capacity. Obviously, if the cell does not hold a charge at all it’s completely dead.
> 2. Is it OK to mix the new cell with the old one? (in case not all cells are die)
The cells you use should all be at the same stage of life (either all old or all new). Otherwise your battery will only last as long as the weakest cell.
> 3. How to determine the problem is the cells or the charging circuitry?
Replace the cells. If it starts working, it was a problem with the cells. If not, it was the charging circuitry, replace that.
Jay
thanks a lot Jay, I hope you dont mind for more question. I want to test my old bat.
How can I recharge the battery without my laptop? can I just connect them to an adapter? If my battery is 3.6V what voltage should I set the adapter?
Thank you
erdwi,
Unless you have a specialized Li-Ion battery charger, you should be very careful charging them directly (without going through the power protection circuit).
I use a CURRENT controlled power supply, and give them 4 volts at 50 mA (0.05 Amps) until the voltage maxes out (usually a day or so).
Jay
Hi Jay,
My battery only lasted at most 10 minutes so I decided to refill it. I used 2600 mah instead of the previous 2200 mah used. I read that the battery will only charge to 2200 mah. Anyway, the newly refilled batteries are working fine. Only one problem, the battery indicator is wrong. After the first charge for about 2 hours, I turned on windows still charging. It said 3% remaining when really it suppose to be 60% or so. The next day it said 4%. Today it says 6% left. I went through 3 cycles do far. Also when discharging, it said 100% , 99 … to 96 (for about 2 hours) then suddenly dropped to 7% critical battery. Could it be the internal flash chip in the battery needs flashing or something? Or it just needs more cycles?
Thanks
Ok, I tried the command with ubuntu
Here are some lines.
So my battery is already fully charging and does not need cycles?
design capacity: 65486 mAh
last full capacity: 65486 mAh
RM:
I would suggest putting the battery through several more full charge/discharge cycles. (The charge control circuit should eventually figure things out.)
The Linux /proc/acpi information looks promising, perhaps windows battery monitor also needs some quality time with the newly rejuvenated battery to figure things out.
Jay
Will the cycles damage the battery because of the discharging? I read that the life of Li-ion batteries lessen when discharged alot. Any way I will still try it. If none of these work, it has to be some chip in the battery?
So here is a summary from the previous cycle
When charging, charge completes at 6% remaining
When discharging, 100% to 96% is about 2 hours. Drops to 7% suddenly. 7% to dead is 30 minutes approx.
One other thing, when discharging, should I let it discharge until hibernation or take off hibernation and let it discharge all? Hibernation is at 2% so that may not be accurate on the battery timer at this time
RM:
You are right, discharging Li-Ion batteries all the way many times will negatively affect the lifespan of the cells. However, doing in five times (especially if you fully charge it afterwards without leaving it sit discharged for long periods of time) will have only a very small effect on the life of the battery. You’ll have to make a decision for yourself if having an accurate battery gauge is more important than eking out the absolute most life from your battery. (Also, if you never charge your battery to 100%, stopping at 90% each time the battery will last a bit longer.)
Re: Hibernation on low battery – Because the point of the discharge/charge cycles is to fix the battery gauge, it’s a good idea to disable hibernation for this procedure and let the battery go until it is fully dead. (You may find that the battery sits at zero percent for a lot longer than you expect….)
Jay
Hi Jay,
Well, the battery never got better after more than 10 cycles. It never says more than 5% charging when it’s fully charged. I would really like the hibernation to work because it would just cut of when the battery is dead.
Do you know about reseting the battery. I saw a guide about opening it up and connecting a cable to a certain chip. The cable connects to the parallel port of the pc. The pc does the rest to reset the battery. Do you know about this? If yes, can you help me?
RM:
It sounds like your battery is set up to assume that the cells will never be replaced (so it cell life setting only goes down). Re-set information would be specific to your laptop brand and perhaps model, and I am afraid I have no suggestions.
Jay
I rebuilt the battery pack for a Dell Latitude C610 with a 66whr battery (rated 4400mah). The eight replacement cells were Tenergy, Li-ion 18650, rated 2600 mah. The results were disappointing. The old cells had a 50 minute life. The new cells last about 60 minutes even after six charge-discharge cycles. I expected 150 minutes. Secondly the new batteries cost about $70. A new aftermarket Dell battery costs about $105.
Frank:
That performance sounds correct. Your original battery had 8 cells (arranged in four banks of two) for a 14.4v total voltage and 4400mAh total power rating.
Your new battery has 8 cells (again, in 4 banks of 2) for 14.4v total voltage and 5200 mAh total power rating. (Power/current is calculated by the cells in parallel, while voltage is calculated by the cells in serial.)
I would expect your new battery to last 1.18 times longer than the original battery (5200/4400 = 1.18; 50min * 1.18 = 59.00min).
However, if the 50 min life figure was from a “used up” battery, I would expect the new cells to do much better, and if they are not you may be experiencing a problem where the battery control circuit isn’t allowing you to “use” the full amount of power in the cells. Have you tried leaving the laptop on even when the reported power level drops to 0%?
Jay
You are right! With apologies to Shakespeare, the fault dear Brutus is not in the batteries but in the control circuit. By disabling the power management alarms under Windows the batteries can last upwards of 160 minutes. The power level drops steadily to 3% during the first 60 minutes then stays there for another 100 minutes. The alarm’s minimum value is 4%. Bother!
I tried booting Linux which gives more information about the state of the batteries. It reports that the “maximum” charge is about 30% of capacity. The voltage is a more accurate measure of the state of the charge. Apparently it is not used to estimate remaining battery life.
Various internet articles suggest that the control circuit can be re calibrated by letting the power drop to zero before recharging but that hasn’t yet worked for me. If it automagically starts to do so, I’ll let you know. In the mean time I won’t complain too much because I can now spend 2+ hours at the bagel shop before I have to look for an outlet. I just have to keep an eye on the power meter.
Hi Jay,
I tried repacking my toshiba tecra s1 laptop with (some) sucess. I cracked open the battery(opened very nicely) and i removed the old cells and replaced them with ones from a hp battery. I drained the cells, then mounted them exactly the same way as the old ones. One problem…the battery charges rrrrrealy slow (60% in the last 30 hours). Also it doesnt seem to want to run on battery, only works with ac adapter plugged in. Any advice ?
Thanks.
How on earth do you pry open ThinkPad battery cases? Awhile back, someone asked this question, and the suggestion was to use a plastic tool used to open cell phones. But how do you even get the plastic tool to work? I tried a mini flat blade metal screwdriver, but can’t seem to even get it into the seam, what more a plastic tool with a thicker blade. Even if you could somehow get the tool in, and then twisted it to pry the case apart, it seems that the plastic tool would break. Am I missing something?
Azakki:
It’s not easy to pry open the batteries. (I left a few pry marks on the side where I started.) You may need to start off with a very thin blade screwdriver. Once you have it cracked open a little bit, you push the plastic tool inside the crack, and then slide the plastic tool along the crack all the way around. It sometimes helps to have two plastic tools, one right after the other. Twist the one in the back to widen the existing crack, and push the one in the front forward to hold it open. Then move the one in the back farther up and repeat.
Jay
I have the exact problem as frank. The control circuit is not used to the new batteries so they dont report full life. 100% charging for me is 4%. Can letting the laptop cut of when the batteries run dry damage the laptop? It just cuts of when dead. The hibernation is of because of the 4% thing. Also the charging light is on for very long, like at least 5 hours. Can the battery be overcharging?
Thanks
Hi,
I would like to ask two questions please.
I reconstructed an external battery pack for my vaio laptop with 6 Ni-MH cells serially 1.2 x 6 = 7.2 V
each one has 2400 mAh.
I connect this battery poles (+) and (-) separately to the corresponding ones on laptop battery location jack. I know I charge my battery outside notebook with an external charger. My notebook works good but there is no battery meter !
First: what are those poles on the laptop inbewteen (+) and (-) poles ?
they are not connected in my reconstructed circut, is there any hazard ?
Second: can I connect both batteries (my reconstructed one (Ni-MH 7.2V 2400 mAh) and that original one of notebook (lion 7.4 v 2600 mAh)) in parralel manner at the same time ?
Thank you.
M.F. Sherif:
The other connections between the Positive and Negative (ground) terminal are used by your computer to communicate with the charge & control circuit that should be in the battery.
Note that when you take a LiIon battery apart, it typically has a small circuit board that handles the actual charging and discharging of the batteries. This circuit ensures two things:
1) That the battery cells do not get charged “to quickly” and overheat, possibly bursting and releasing Hydrogen gas (and possibly burning or exploding).
2) That your laptop does not discharge the battery too quickly (also resulting in overheating, off-gassing, and possible fire/explosions)
Your laptop MAY draw power from a battery without a charge/control circuit, and it would probably be safe, but I would be very surprised if the laptop would CHARGE the battery before hearing an “everything is OK” signal from the charge/control circuit.
If the laptop DOES provide power to the battery (for charging) and you do not have a charge/control circuit, you risk the battery overheating and burning or exploding.
My major point: Do not use liIon cells without the proper charge/control circuit. The easiest way to get a charge/control circuit is by taking apart a broken battery (although sometimes they are designed to stop working once the battery cells are used up.)
As for your “in parallel” question. The correct way to add more power capacity to your battery is AFTER the charge control circuit. (i.e. put a new cell in parallel with each existing cell to double your capacity).
Note that (newer) charge control circuits manage each cell individually, so putting two cells in parallel where it expects one will work OK, but the two cells will be treated as a single cell, so they should both be of the same “age” when you start. If one cell is old and one cell is new, they will be mismatched and it won’t gain you much.
Jay
Hi !
I have a IBM ThinkPad X31 too and its battery is close to death (30mins of using on batteries).
I’m planning to buy some batteries, but as i found Ultrafire 3000mAh 18650 batteries on ebay, i’m just thinking of about gaining 6Ah of battery instead of 4.4Ah original capacity.
What do you think of it ?
As the cells capacities are superior than the original ones, it would logically not be a problem for the electronic embeded into the pack to charge them fine.
Waiting for your advice to get the right decision.
Simkard,
Original X31 batteries were rated at 4.4AH (using pairs of 2200mAh cells). New X31 batteries are usually rated at 4.8ah (using pairs of 2400 mAh cells). You are correct that 3000mAh cells would theoretically give 6Ah of capacity.
However, this is the first time I’ve seen 3000 mAh 18650 batteries, and since I can only find 3000mAh cells listed on Ebay, you should confirm that they are indeed rated as 3000mAh batteries according to industry standards. (Many cells will do better than their rating at the beginning of their life, but typically cells that are rated as “2400″ or “2200″ mAh are guaranteed to provide that capacity for a certain number of charge cycles, etc. These 3000 mAh batteries may just be 2600 mAh cells that happen to give 3000 mAh on the first few charge/discharge cycles, but are really no better than 2600 mAh cells. [Or, they could be a brand new cell that is just better than older ones...]
The link you sent advertised them as having “short-circuit and over-current protection”, so they may already contain charge control electronics that you would have to remove before using. I have found 4pc of 18650 @ 2600mAh for $25, so the $35 price seems appropriate.
Jay
My battery is fine. It just won’t charge. Apparently a diode on the motherboard has closed and the AC circut doesn’t work. laptop works fine on battery. just can’t get it to charge. Have you ever made an external battery charger?
Sanford,
I have not built an external charger, let us know if you get one working.
Jay
Hi there, thank you so much for this site. I have a Ibook Rechargeable Battery Model M8403. Please advise if it will be possible to repack this battery and where i can get the cells. I reside in Cape Town , South Africa.
Thank you and God Bless.
Tim
About the battery chip, I have an idea,
will it charge if we don’t actually disconnect the old battery pack until we put new cells.
The idea is to open the case, remove all old batteries together with electronics,
put new cells into the empty case and parallely connect new and old cells, only than when electronics are wired with the new cells disconnect them from the old ones. I’m not much of an expert but theoretically I think they should work?
Bardh:
By doing this (carefully swapping in the new cells) you could keep the charging chip from realizing that the cells had been changed. However, the chip may keep an internal variable that keeps track of how much power is “left” in the cells, and every so often it will decrement the variable, but it is never allowed to increment the variable.
So, depending upon how the programming works, you may or may not be able to get more performance from your “new” battery. Try it out and let us know how it works.
Jay
I’ve replaced the cell of my laptop (IBM ThinkPad R51 2887 MQ6) accourding to your suggestion, Now my laptop is not running on battery ( it runs well on AC power ). in IBM powermanagement software it shows that battery is in good condition but amp-hour is 0.00 , what happened to it?? will you suggest me what should I do now…
Jatin,
Things to check:
1) A wire is not correctly connected and one or more of your cells is not currently connected to the power circuit. Open the battery up again and look for loose connections and make sure all of the solder joins are good.
2) Try the battery in a different laptop. and try the laptop with a different battery to isolate the problem to the battery or laptop. (I’d expect the problem is with the battery, but you never know…)
It is possible that your particular battery has a power circuit that does not allow refills. If you find the solution to your problem, please let us know.
Jay
I’ve check the connections of the battery is looks like all is good …. but now I find out the problem, there is a EEPROM in by battery pack which contains the data for my battery now I need to reset that EEPROM … I’ve Linux script to reset the EEPROM ..I’ll try to reset it this weekends
Regards
Jatin,
Good to know that a software fix exists. Can you post a URL for where to find the script?
Jay
Hi, I just replaced my 4 cells in a Thinkpad X60 Battery. I have a similar problem as Jatin:
– Laptop doesn’t start from battery
– When the power cord is connected, the battery sign blinks orange
– When starting the computer, battery status informs that “irreparable dammage”
It seems that while rebuilding the cell, the chip’s error bit was set. There are programms to reset Eeproms of SMBus based battery packs (AccPlus, SBWorkshop). I was wondering if it’s possible to use an Parallel port to SMBus adapter and reset it with Linux Software.
Does anyone know the pinout and specifications of thinkpad battery connectors?
Thanks for the interesting story. Just curious: why do the cells need to be soldered? Can they be used touching (under spring tension), safely?
Tim,
LiIon cells do not typically have “nubs” at the top like a standard AA battery, so pushing them together will not necessarily make electrical contact. (Plus, laptop battery cases do not have springs.)
If you made sure that each battery had good electrical contact with the next one, and had a spring to hold them under tension, I see now reason you could NOT hold them together with springs, but I suspect that a soldered connection has better electrical properties.
Jay
hello, i got a thinkpad t23, the batteries
are the same, the red ones.
I need of 10,8 Volt and 4.400 mAmpere
please can you tell me the correct URL to watch ? http://www.bateryspace.com and the other part of the URL which is ?
awaiting your reply,
Paolo
Paolo,
You can purchase any of the 18650 batteries. They come in various different capacities and costs, but any 18650 battery will physically fit.
Jay
I haven’t tried it yet but, I think a spark plug gapping tool might help to open up the battery packs a little.
[...] sono quelle fatte a macchina con saldatura a punti. vedi qui, un esempio da cui mi sono "ispirato": Jay’s Technical Talk � Refilling laptop batteries! comunque io sono andato bene, alla fine la batteria dura 40-45 minuti (prima non durava 3 minuti). [...]
[...] http://www.summet.com/blog/2007/02/17/laptop-battery-refill/ [...]
For those of you who are having probs with your new packs not charging. Most smart chips memory is erased when power is lost and therefore wont charge anymore. Never disconnect power from the chip hook up a secondary source with a 100k ohm resistor and dont remove it until your new pack is hooked up to the chip.
Before removing my old cells, should I make sure they are empty? If I remove them when they are supposed to be fully charged is that a problem?
Also, if I get 2600mAH cells instead of 2400mAH ones like those in my battery, will I get a battery that lasts longer or am I just going to waste money because the laptop will treat them as 2400mAH cells anyway?
Clive:
Li-Ion Cells store best at around 40% charge. If you are just going to throw them out, you could discharge them lower than this, but I don’t see a big point in doing so. Assuming you recycle them in a proper battery disposal location, they will know how to handle them correctly, charged or not.
If you purchase better (higher capacity) cells than you currently have you should get a better (longer) run-time.
Jay
Hello Jay,
First of all, thank you for your quick answer. I was afraid it would take days to get a reply, but a few hours after sending my message I checked your site again and here was your reply. Thank you!
I guess I didn’t explain myself properly about discharging the cells or not before removing them. What I meant is before putting new cells in my battery is it better to have the old ones fully charged so the electronics on the battery will see the cells as 100%? Does is make any difference at all if the old cells were at 100% before being removed? Hopefully, this is clearer this time.
Clive:
The electronics will have to re-adjust themselves to your new cells over the next several charge/discharge cycles, so where the old cells were shouldn’t matter.
Jay
Thanks for your infos jay !
And sorry for saying: Appearently most of the people here have BY FAR NO idea of how dangerous this “soldering around” is in fact. BR
Wow, almost 2 years and still replying to comments
Well done. I have recently needed to hack laptop batteries and this site come up in a search. I needed a really long runtime and got it. I was fortunate enough to get hold of some New Old Stock cells for cheap. 20Amp Hours on a IBM T41 goes a long way, unfortunately it does not fit in the original case. I can share a trick to opening up some packs, use a sharp hobby knife/craft knife/boxcutter to cut a wider slot at the seam so you can fit your tool in to start prying.
Hey man,
I just did your little trick on my nearly 4 year old fijitsu siemens pi1536 and it worked perfectly!!
First time it charged in little over an hour, and I then proceded to run battery eater pro v2.70 when it said I had just 20 min over battery time
But it stuck at 7,4% and it’s still there now after an hour of hardcore processing. So I’m a very happy man!
By the way I had huge difficulty getting the batteries out without destroying the cartrige, which I ended up doing. But I taped somthing up and now I’m home free
Thanks again!
Greetings for The Netherlands.
Terrific post! I had read this before and just revived my old Averatec battery with cells from my wife’s Dell. It works great!
Interesting point about the gradually increasing capacity. I have started off at 1236mAh and will see if I can work it up all the way to 4400mAh.
PS. You might remember me from GSC at Tech.
Hi Tejas!
It’s not so much increasing capacity, as getting the batteries power electronics to recognize the improved capacity.
Jay
Hi Jay!
Ubuntu refuses to discharge my laptop all the way, so initially the capacity refused to increase. However, I discovered that the laptop’s BIOS has a “battery calibration” feature where it does a full charge-discharge cycle, and bumps up the learned capacity.
I guess this is similar to Surfboy’s situation above (#24), where he ended up using Windows’ Power Meter.
Hi Jay
Good on you for your patience with this many questions answered over so quite a few yrs.
My question:
I’m about to rebuilt my Dell Latitude D620 6 cell pack.
However, here and there I read that I should use “Unprotected” cells for replacement.
I have even seen recommendations to REMOVE the protection circuit from each cell before inserting and connecting them, in case one is using a “Protected” cell as replacement.
The rationale is that the pack’s built-in protector and the cells’ protectors might not like each other and cause conflict.
On the other hand when I look at the OLD cells they clearly seem “Protected” as I can see the notch at one end of each cylinder as well as a stripe along the cells, running underneath the shrinking wrap.
Now could you please shed some light on this issue and get me out of this confusion?
Thanks in advance
Omid,
My laptop had “unprotected” cells, and I replaced them with the same.
If your laptop is using a cell with a built in protection circuit, my advise (with no real knowledge to back it up) would be to replace them with the same thing.
Jay
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